Trends in Innovative Treatment Technologies at Contaminated Sites

Kovalick, Walter W.

doi:10.2166/wst.1992.0390

Cited by 14 publications

(5 citation statements)

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“…Pseudo-first-order rate constants for these experiments are presented in Table 2 (exp. [1][2][3][4][5] and are plotted against Fe(II) dose in Figure 2(a). As shown in Figure 2(a), the rate constant increased nearly linearly with Fe(II) dose at low values and approached a maximum at high doses.…”

Section: Resultsmentioning

confidence: 99%

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Reductive Dechlorination of Tetrachloroethylene by Fe(II) in Cement Slurries

Hwang

Batchelor

2000

Environ. Sci. Technol.

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Fe(II) is a potentially effective reductant for treating chlorinated organics in soils by degradative solidification/ stabilization (DS/S) process. DS/S is a modification of conventional S/S that promotes degradation of organic contaminants while immobilizing inorganic contaminants. In this study, degradation of tetrachloroethylene (PCE) by Fe(II) in the presence of cement hydration products was characterized by using batch slurry reactors. Cement has been found to catalyze or participate in the PCE degradation reactions over the pH range investigated (10.6-13.8), and the degradation kinetics can generally be described by a pseudo-first-order rate law. PCE degradation rate was greatest at pH ∼12.1 with a half-life of 4.1 days when [PCE] 0 ) 0.245 mM and [Fe(II)] 0 ) 39.2 mM. Under this condition, 98% of the PCE initially present in the system transformed to nonchlorinated products (acetylene, ethylene, ethane) with acetylene being predominant, implying that elimination pathways were favored in the cement systems at high pH. Production of chlorinated intermediates was minimal in Fe(II)/cement systems. Addition of Fe(III) to Fe(II)/ cement systems increased PCE degradation rates by factors of ∼2 to 3, suggesting Fe(II)-Fe(III) (hydr)oxides might have been reactive agents. Three hypotheses for the reaction mechanisms are discussed.

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Section: Resultsmentioning

confidence: 99%

“…Solidification/stabilization (S/S) is the most commonly used remedial alternative at superfund sites in the United States (1). Degradative solidification/stabilization (DS/S) is a modification of conventional S/S processes that promotes degradation and containment of organic contaminants while also immobilizing inorganic contaminants.…”

Section: Introductionmentioning

confidence: 99%

Reductive Dechlorination of Tetrachloroethylene by Fe(II) in Cement Slurries

Hwang

Batchelor

2000

Environ. Sci. Technol.

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“…Microbial degradation has been proposed as an efficient strategy for organic waste removal and it has distinct advantages over physico-chemical remediation methods; as it uses relatively low cost, low technology techniques, and may be carried out on site to achieve the complete degradation of organic pollutants without collateral destruction of the site material or its indigenous flora and fauna [5]. Also, biological processes and biodegradation of organic contaminants to innocuous end products (CO 2 , cell mass, water) minimizes the environmental impact and residual contamination [6,7]. However, anthropogenic chlorinated organic pollutants are now dispersed throughout the environment and can be highly recalcitrant to biodegradation processes found in most naturally occurring microorganisms.…”

Section: Introductionmentioning

confidence: 99%

Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

Olaniran

Balgobind

Pillay

2013

IJMS

499

197

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Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation), treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals.

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“…Physical, chemical and biological approaches can be used to remove xylene and other petroleum hydrocarbons from contaminated sites. Microbial biodegradation is less expensive and hence considered one of the most promising alternative methods for cleaning up the environment from petroleum hydrocarbons (Kovalick, 1992;Vidali, 2001;Jahn et al, 2005;Vieira et al, 2007;Das and Chandran, 2011;Alrumman et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Screening and Characterization of Aerobic Xylene-Degrading Bacteria from Gasoline Contaminated Soil Sites Around Gas Stations in Northern Jordan

Irshaid¹,

Jacob²

2015

J. of Biological Sciences

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A B S T R A C T Xylene is frequently released into the environment from biomass. As a consequence of this, its bioaccumulation can cause adverse health effects in humans. The purpose of this study was to screen for aerobic xylene-degrading bacteria from gasoline contaminated soil sites located around gas stations in the city of Al-Mafraq, Jordan. The effects of some physicochemical factors were examined. The 10 g of soil sample were transferred to Stanier's mineral medium supplemented with 1% m-xylene and incubated at 30°C for 72 h. At least 4 aerobic m-xylene degrading isolates, designated as X1-X4 were identified using biochemical and molecular biology techniques. Isolates X1 and X2 were rod-shape Gram negative, oxidase and catalase positive bacteria. Isolate X3 was a rod-shape and Gram negative bacterium that was catalase positive and oxidase negative. Isolate X4 was a rod-shape, spore forming and Gram positive bacterium that was oxidase and catalase positive. Isolates X1, X2 and X4 showed high similarity to Pseudomonas aeruginosa, Pseudomonas stutzeri and Bacillus firmus, respectively, whereas X3 was a novel species of the genus Citrobacter, similar to Citrobacter amalonaticus. The growth rates of these isolates were slower at 2% m-xylene than at 1% m-xylene. The growth rate was less when the temperature was reduced from 30-25°C, whereas, at 45°C, the growth rate almost completely ceased. The growth rate was higher at pH 6.5 than at pH 5.5 or 8.5. The shortest generation times were found to be 8 h for Bacillus firmus, followed by 9 h for Pseudomonas stutzeri, 10 h for Citrobacter amalonaticus and 11 h for Pseudomonas aeruginosa under 1% m-xylene at 30°C and pH 6.8. In conclusion, we reported for the first time the isolation of four bacterial species with the ability to utilize m-xylene as a growth substrate.

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Trends in Innovative Treatment Technologies at Contaminated Sites

Cited by 14 publications

References 0 publications

Reductive Dechlorination of Tetrachloroethylene by Fe(II) in Cement Slurries

Reductive Dechlorination of Tetrachloroethylene by Fe(II) in Cement Slurries

Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

Screening and Characterization of Aerobic Xylene-Degrading Bacteria from Gasoline Contaminated Soil Sites Around Gas Stations in Northern Jordan

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